Art of annealing wire



UNITED STATES PATENTI OFFICE- JAMES o. MUSTIN, OF KNOXVILLE, PENNSYLVANIA.

ART OF ANNEALING WIRE.

SPECIFICATION forming part of Letter- Patent NO. 489,194, dated January 3, 1898. Application filed February 18, 1892. Serial No. 421,947- (Ho model.)

, .To alt whom at my concern: erly heat the articles passing therealong, is 3e it known that I, JAMES G. MUSTIN, a placed a body of sand of suitable depth, say c tizen of the United States, residing at Knoxfive or" six inches. to entirelycover either the ville, 1n the county of Allegheny and State of wire or sheet metal passing through the cham- 55 5 Pennsylvania, have invented or discovered ber. The sand is retained at the sides of the certain new and useful Improvements in the hearth by upwardly projecting walls 6, and Art of Annealing Wire, of which improveis prevented from being drawn by the movements the following 1s a specification. ment of the wire or sheet metal out of the lhe lnventlon described herein relates to chamber by a partition wall 7. In the front 60 to certa n improvements'in annealing wire, sheet wall of the chamber 1 and also of the partimetal, &c. In working both wire and sheet tion 7, are formed slots or openings 8 and metal the drawing and rolling operation to 9, the opening 9 permitting of the passage of wn ich they are sub ected so hardens the mathe wire from the'chamber 1 to the chamber tonal as to necessitate a softening or anneal- 2, in which is placed another body of sand de- 65 r 5 mg thereof before they can be further reduced signed for the gradual cooling of the wire or or used 111 the arts. To prevent the scaling sheet metal. The body of sand in the chamof the metal of the wire or sheets during this her 1 having been properly heated, to annealannealing operatlon, great expense is ining temperature the wire or sheet metal is curred. It 1s well known that when iron or passed in through the opening 8 into the 70 so steel is subjected to atmospheric influences body of sand in the chamber 1,, and then,

when at ahigh temperature, oxidation is very drawn along through such body of sand at 1-ap1 d. To overcome the loss due to oxidation such 'a'rate as will insure the raising of the during annealing operations, many devices wire or sheet metal tothe proper temperature have been employed, but none, as yet, praci. e; about a cherry red. Then the wire or 75 :5 tlcally successful. y sheet metal passes into the body of sand in The ob ect of this invention is to protect the chamber, 2, thence along through such the mm or sheet from the inception to the end body of sand and out through the opening or of the annealing operation, from all access of slot 10 in the rear wall of the furnace. air, thereby preventing either entirely or to a It will be readily understood that, although 80 great extent the oxidation of the surface. a the partition 7 will prevent the access of pro- In the accompanying drawings forming a ducts of, combustion to the chamber 2, yet the part of this specification, Figure 1 is a sec- .portions of the body of sand in said chamber tional elevation of a furnace adapted to the '2 will be considerably heated, and such porpractice of my invention. Fig. 2 isa perspections will be further heated by small portions 85 tive view of the same,-looking toward one of of sand .drawn from the chamber 1 by the the rear corners, and Fig. 3 is a vertical secmovementof the wire or sheet metal from one tion on the line w. m. Fig. 1. to the other of said chambers. In order to In the practice of my invention I provide a prevent the body of sand in the chamber 2 furnace of suitable construction as regards being too highly heated by radiation from the o 40 its length and breadth, in which I form two chamber 1, or by sand drawn from the chamchambers 1 and 2, the front chamber 1 is arher 1, a stack 17 is arranged at the front end ranged immediately over the fire chamber 3, of the chamber 2, so that the heat in the front so that the combustion in said chamber will end of said chamber, passing up through said heat the hearth of the heating chamber 1,a.nd stack will create a draft of cold air through 5 the products of combustion passing up the opening 10 at the rear end of the chamthrough lateral flues 4, will flow over the top ber.2 and through the sand, which is mainof the hearth, and thence to the stack 5, which tained in a loose, open condition by the pasis so located that the products of combustion sage of the wi1'e,,sheet metal &c., whereby will flow uniformly over the top of the'hearth the portionof the sand adjacent to the open- I03 of the heating chamber 1. Upon the heart-h ing 10 in the chamber 2 is maintained at 1,whi.ch is made of a suflicient length to propatmospheric temperature. It will be readily understood that the passage of the wire through these bodies of sand will cause a How, as it were, of the sand from the frontto the rear end of the furnace, and at the rear end the sand will be drawn entirelyeutof the chamber 2. In order to compensate for this loss of sand and to maintain the beds at a uniform depth, an inclined chute 11, is arranged below the opening in the rear wall to of the furnace, which will conduct the sand to a suitable receptacle 12,,at one side of the furnace, from which it'is drawn up by a suitable arrangement of buckets 13, on a belt or chain 14, and discharged into an inclined l5 chute 15. This chute will conduct the sand to an opening 16 in the top wall of the furnace at or near the front of the chamber 1, thereby maintaining an abundant supply of sand at that point, which will be evenly diszo tributed through the chambers 1 and 2, by the movement of the wires or sheet metal.

It will be readily understood that by highly heating the sand in the chamber 1, all or nearly all the air contained therein will be 2 5 driven out, and hence, the wire or sheet metal will be protected from atmospheric influences while being heated. It is also true that the air will be driven out of the portions of the sand in the chamber 2 adjacent to the parti- 0 tion 7, such portions being heated as hereinbefore stated, so that the wire will also be protected from atmospheric influences during the initial cooling of the same. It will also be readily understood that the portions 5 of the sand in the chamber2 will have a temperature approximately that of the sand in the chamber 1, and that such temperature will gradually decrease in proportion to the distance from the partition 7 I am z'ware that it is not new to employ a body of sand for heating wire to the desired temperature either byEburying coils of such wire in the body of and, or by drawing it through a suitable bo y of sand heated by a 5 furnace. But in these several operations the wire is subjected as soon as properly heated to atmospheric influences so that oxidation w1 ll occur, or else in the case of burying the coils in the body of sand they are allowed to remain therein until the whole is properly cooled. This, however, is impracticable on account of the long time required to reduce the sand and wire to the proper temperature. It is characteristic of my invention that the wire or sheet metal is kept in movement constantly during the entire annealing operation, and is protected from atmospheric influences from the time at which it is raised to a suflieient temperature to be easily sub- 6o ject to oxidation until it is cooled to a temperatureat which oxidation will cease. It is further characteristic of my invention that the wire or sheet metal is subjected to a con-. tinuous operation,that as soon as the wire is '65 drawn from one coil in front of the furnace,

'its rear end is connected tothe end of another coil, thereby permitting of theconstant operation of the furnace. It is not necessary that the partition 7 should extend down into the body of sand, but may be so ariangedas to prevent the entrance of the products of combustion from the chamber 1 to the chamber 2, so that the two bodies of sand, as they have been heretofore described are practically one continuous body of sand, one portion thereof being highly heated, and the temperature of the remaining portions gradually decreasing until at the rear end the body of sand has a temperature equal or approximately so to the atmosphere.

I am aware that it has been proposed to harden and temper wire for wire cards, by

passing the wire after it leaves the hardening bath through a box or trough containing slaked lime heated to a temperature below a red heat or the heat required for the purposes of annealing, dependent upon the temper desired in the finished prod uct,and then through a box or trough containing cold slaked lime, the heating and cooling boxes being separated by a slitted partition to prevent the heat and heated material from passing into the cooling box or trough. This method differs from mine in that the wire is not heated to a sufficient temperature to properly elfect the annealing thereof. If in tempering, the wire is heated to a red heat the eflfect of the previous hardening is entirely destroyed, whereas in annealing it is desirable to heat the wire to at least a cherry red and then gradually cool it down. This difference between tempering and annealing is well known and recognized in the art. The doing of the one does not teach the other.

I claim herein as my invention:

1. As an improvementin the art of annealing wire, sheet metal, 850., the method herein described, which consists in passing the wire or sheet metal through a body of sand having a portion at one end thereof heated, to an annealing temperature, about a cherry red and the temperature of the remaining portion gradually decreasing toward the op posite end whereby the wire or sheet metal passing through such body of sand is highly heated'and cooled while protected from atmospheric action, substantially as set forth.

2. As an improvement in the art of 'anneal ing wire, sheet'met-al, &c., the methodherein' described, which consists in passing wire,

sheet metal, &c., through a body ofsand,

heated to an annealing temperature, about a cherry red and then through another body of sand having a portion thereof approximating the temperature of the highly heated body of sand and gradually decreasing in tempera ture to that of the atmosphere, substantially as set forth. Y

3. In 'an apparatus for annealing wire, sheet metal. &c., the combination of a furnaee provided with a heating chamber, a body of sand arranged in the hearth of the heating chamber so as to be subjected to im mediate contact of the heat and products of.

combustion from the fire chamber of the fur nace, which is connected to the heating chamber, and a cooling chamber adjacent to the heating chamber and provided with air inlets and outlets, and a body of sand located in the cooling chamber and arranged so as to be directly subjected to the cooling action of a current of air passing through the cooling chamber, the walls of the heating and cooling chambers having suitable openings for the passage of the wire, &c., into and through the same, substantially as set forth. 4. In an apparatus for annealing wire, sheet metal, &c., the combination of a heating chamber having a body of sand therein, I5 a cooling chamber having a body of sand therein, openings through the walls of said chambers for the passage of wire or sheet metal therethrough, and means for conve ing sand from the rear end of the cooling 2o chamber to the front end of the heating chamber, substantially as set forth.

In testimony whereof I have hereunto set my hand.

. JAMES G. ,MUSTIN. Witnesses:

DARWIN S. WOLCOTT, CHARLES 1?. ROBINSON. 

